Heterosis

Heterosis describes the superior performance of heterozygous hybrids compared to their genetically diverse parental inbred lines. Heterosis is extensively exploited in agriculture for more than 100 years. Nevertheless, the underlying molecular basis remains largely enigmatic. Heterosis is not only manifested in adult plants in traits like plant height or yield but can already be observed during embryo and early seedling development. The classical dominance model of heterosis explains the superiority of hybrid plants by the complementation of deleterious parental alleles by superior alleles of the second parent. Genes active in one inbred line and the hybrid but inactive in another represent an extreme instance of allelic diversity defined as single parent expression. Thus far we were able to demonstrate that a large set of such genes consistently display expression complementation in a diverse set of maize hybrids in different tissues and along different developmental stages of primary roots. As a consequence of expression complementation, hundreds of genes are additionally active in hybrids.

Our reviews on the molecular dissection of heterosis

Baldauf J and Hochholdinger F (2023) PubMed
Hochholdinger F and Baldauf J (2018) PubMed
Paschold A et al. (2010) PubMed
Hochholdinger F and Hoecker N (2007) PubMed

Publications of our group on the transcriptomic dissection of single parent expression complementation in maize hybrid

In primary roots

NCBI SRA accession SRA049019; Paschold et al. (2012) PubMed

In primary roots in response to drought

...after PEG treatment: NCBI Bioproject accession PRJNA284670; Marcon et al. (2017) PubMed

In primary root tissues

… in the meristematic zone, elongation zone, cortex and stele tissues of primary roots: NCBI Bioproject accession PRJNA218555; Paschold et al. (2014) PubMed, Baldauf et al. (2016) PubMed

In primary roots of a panel of diverse inbred lines

… including the genotypes B73, Mo17, W64A, Oh43, H99, A554, H84: NCBI Bioproject accession PRJNA392500; Baldauf et al. (2018) PubMed, Baldauf et al. (2020) PubMed

In field grown aboveground vegetative and generative tissues in a panel of diverse inbred lines

…including unpollinated ears, meiotic tassels and youngest fully developed leaf in the genotype panel used in Baldauf et al. (2020): NCBI Bioproject accession PRJNA705557; Baldauf et al. (2022) PubMed